docs: def tagged(self, tag, predicate=None, index=None):
          """
          Retrieves a set of Match objects that have the given tag defined.
          :param tag:
          :type tag: str
          :param predicate:
          :type predicate:
          :param index:
          :type index: int
          :return: set of matches
          :rtype: set[Match]
          """
          return filter_index(_BaseMatches._base(self._tag_dict[tag]), predicate, index)